User interface (UI) facilitates interactions between users and machines. Users use UI to operate machines, while machines may provide feedback to users via UI. Graphical user interface (GUI) is a type of UI that allows users to interact with machines, e.g., through graphical icons and visual indicators. Traditional GUI is displayed on a two-dimensional (2D) setting. 2D refers to objects or images that show only two dimensions, while three-dimensional (3D) refers to objects or images that show three dimensions.
Virtual reality (VR) is computer-simulated reality that replicates an environment using computing technologies and simulates a user's physical presence and environment, e.g., to enable user interaction with the VR to an extent. Partially because depth is added as a factor in VR's 3D environment, VR can yield a highly immersive experience. The depth factor is commonly implemented by forcing the eyes to converge differently for virtual objects at different distances.
It is often problematic to insert a 2D object into a 3D environment. By way of example, inserting an object of 2D GUI into 3D VR may break the user's immersive experience by requiring the eyes to converge at a new location with a different depth. On the other hand, the newly inserted 2D GUI may be unexpectedly embedded into a 3D object. Conversely, the newly inserted 2D GUI may block another 3D object.